Beginner warning: Details follow which you may not wish to read at your current level.

The Draught of Living Death brings upon its drinker a very powerful sleep that can last indefinitely. No antidote is mentioned in the books, though presumably there must be one.

This potion is mentioned by Professor Snape in Harry's first-ever Potions lesson. Snape asks Harry what he would get if he were to mix the root of Asphodel and an infusion of Wormwood; Harry, of course, cannot answer.

It is mentioned again in Harry Potter and the Half-Blood Prince. In Professor Slughorn's first NEWT Potions class, the class members are called upon to produce the Draught of Living Death. At this point we find that this potion also contains sopophorous bean juice and chopped valerian root, probably among other ingredients.

We do not, of course, learn the full set of ingredients for the Draught at any point. We do learn that the standard instructions do not produce as effective a Draught as is possible. Harry finds that the marginal comments in his textbook specify alterations to the standard formulas. Changes to the Draught of Living Death include crushing the sopophorous bean rather than cutting it, and stirring once clockwise after every seven times counter-clockwise, rather than continuously counter-clockwise. Following the marginal instructions results in Harry getting better results than Hermione, who is of course following the book's instructions precisely.

In the American edition of Harry Potter and the Half-Blood Prince, Professor Dumbledore, reasoning with Draco Malfoy, says that if Draco chooses to abandon the mission he has been given, Dumbledore can protect him and his family, by making it seem that they are all dead, if necessary. One wonders whether the Draught of Living Death, or some derivative of it, would be involved in such a ruse.